Update absl::allocator_traits and absl::pointer_traits to always

use std::allocator_traits and std::pointer traits.

Note that the reason given in the comments for these implementations was
incorrect. Both of these exist in C++11, but not all compilers had
working implementations, so Abseil backfiled them. All supported compilers
now have working implementations.

https://en.cppreference.com/w/cpp/memory/allocator_traits
https://en.cppreference.com/w/cpp/memory/pointer_traits

Documentation has been updated to recommend the std:: spellings.

Fixes #1366

PiperOrigin-RevId: 503532746
Change-Id: Ia437f65a4c752581195dc582a41831b479d096c6

1 files changed, 0 insertions, 332 deletions

diff --git a/absl/memory/memory_test.cc b/absl/memory/memory_test.cc
index 6f01cdff..fafd3a41 100644
--- a/absl/memory/memory_test.cc
+++ b/absl/memory/memory_test.cc
@@ -190,338 +190,6 @@ TEST(RawPtrTest, NotAPointer) {
 }
 */
 
-template <typename T>
-struct SmartPointer {
-  using difference_type = char;
-};
-
-struct PointerWith {
-  using element_type = int32_t;
-  using difference_type = int16_t;
-  template <typename U>
-  using rebind = SmartPointer<U>;
-
-  static PointerWith pointer_to(
-      element_type& r) {  // NOLINT(runtime/references)
-    return PointerWith{&r};
-  }
-
-  element_type* ptr;
-};
-
-template <typename... Args>
-struct PointerWithout {};
-
-TEST(PointerTraits, Types) {
-  using TraitsWith = absl::pointer_traits<PointerWith>;
-  EXPECT_TRUE((std::is_same<TraitsWith::pointer, PointerWith>::value));
-  EXPECT_TRUE((std::is_same<TraitsWith::element_type, int32_t>::value));
-  EXPECT_TRUE((std::is_same<TraitsWith::difference_type, int16_t>::value));
-  EXPECT_TRUE((
-      std::is_same<TraitsWith::rebind<int64_t>, SmartPointer<int64_t>>::value));
-
-  using TraitsWithout = absl::pointer_traits<PointerWithout<double, int>>;
-  EXPECT_TRUE((std::is_same<TraitsWithout::pointer,
-                            PointerWithout<double, int>>::value));
-  EXPECT_TRUE((std::is_same<TraitsWithout::element_type, double>::value));
-  EXPECT_TRUE(
-      (std::is_same<TraitsWithout ::difference_type, std::ptrdiff_t>::value));
-  EXPECT_TRUE((std::is_same<TraitsWithout::rebind<int64_t>,
-                            PointerWithout<int64_t, int>>::value));
-
-  using TraitsRawPtr = absl::pointer_traits<char*>;
-  EXPECT_TRUE((std::is_same<TraitsRawPtr::pointer, char*>::value));
-  EXPECT_TRUE((std::is_same<TraitsRawPtr::element_type, char>::value));
-  EXPECT_TRUE(
-      (std::is_same<TraitsRawPtr::difference_type, std::ptrdiff_t>::value));
-  EXPECT_TRUE((std::is_same<TraitsRawPtr::rebind<int64_t>, int64_t*>::value));
-}
-
-TEST(PointerTraits, Functions) {
-  int i;
-  EXPECT_EQ(&i, absl::pointer_traits<PointerWith>::pointer_to(i).ptr);
-  EXPECT_EQ(&i, absl::pointer_traits<int*>::pointer_to(i));
-}
-
-TEST(AllocatorTraits, Typedefs) {
-  struct A {
-    struct value_type {};
-  };
-  EXPECT_TRUE((
-      std::is_same<A,
-                   typename absl::allocator_traits<A>::allocator_type>::value));
-  EXPECT_TRUE(
-      (std::is_same<A::value_type,
-                    typename absl::allocator_traits<A>::value_type>::value));
-
-  struct X {};
-  struct HasPointer {
-    using value_type = X;
-    using pointer = SmartPointer<X>;
-  };
-  EXPECT_TRUE((std::is_same<SmartPointer<X>, typename absl::allocator_traits<
-                                                 HasPointer>::pointer>::value));
-  EXPECT_TRUE(
-      (std::is_same<A::value_type*,
-                    typename absl::allocator_traits<A>::pointer>::value));
-
-  EXPECT_TRUE(
-      (std::is_same<
-          SmartPointer<const X>,
-          typename absl::allocator_traits<HasPointer>::const_pointer>::value));
-  EXPECT_TRUE(
-      (std::is_same<const A::value_type*,
-                    typename absl::allocator_traits<A>::const_pointer>::value));
-
-  struct HasVoidPointer {
-    using value_type = X;
-    struct void_pointer {};
-  };
-
-  EXPECT_TRUE((std::is_same<HasVoidPointer::void_pointer,
-                            typename absl::allocator_traits<
-                                HasVoidPointer>::void_pointer>::value));
-  EXPECT_TRUE(
-      (std::is_same<SmartPointer<void>, typename absl::allocator_traits<
-                                            HasPointer>::void_pointer>::value));
-
-  struct HasConstVoidPointer {
-    using value_type = X;
-    struct const_void_pointer {};
-  };
-
-  EXPECT_TRUE(
-      (std::is_same<HasConstVoidPointer::const_void_pointer,
-                    typename absl::allocator_traits<
-                        HasConstVoidPointer>::const_void_pointer>::value));
-  EXPECT_TRUE((std::is_same<SmartPointer<const void>,
-                            typename absl::allocator_traits<
-                                HasPointer>::const_void_pointer>::value));
-
-  struct HasDifferenceType {
-    using value_type = X;
-    using difference_type = int;
-  };
-  EXPECT_TRUE(
-      (std::is_same<int, typename absl::allocator_traits<
-                             HasDifferenceType>::difference_type>::value));
-  EXPECT_TRUE((std::is_same<char, typename absl::allocator_traits<
-                                      HasPointer>::difference_type>::value));
-
-  struct HasSizeType {
-    using value_type = X;
-    using size_type = unsigned int;
-  };
-  EXPECT_TRUE((std::is_same<unsigned int, typename absl::allocator_traits<
-                                              HasSizeType>::size_type>::value));
-  EXPECT_TRUE((std::is_same<unsigned char, typename absl::allocator_traits<
-                                               HasPointer>::size_type>::value));
-
-  struct HasPropagateOnCopy {
-    using value_type = X;
-    struct propagate_on_container_copy_assignment {};
-  };
-
-  EXPECT_TRUE(
-      (std::is_same<HasPropagateOnCopy::propagate_on_container_copy_assignment,
-                    typename absl::allocator_traits<HasPropagateOnCopy>::
-                        propagate_on_container_copy_assignment>::value));
-  EXPECT_TRUE(
-      (std::is_same<std::false_type,
-                    typename absl::allocator_traits<
-                        A>::propagate_on_container_copy_assignment>::value));
-
-  struct HasPropagateOnMove {
-    using value_type = X;
-    struct propagate_on_container_move_assignment {};
-  };
-
-  EXPECT_TRUE(
-      (std::is_same<HasPropagateOnMove::propagate_on_container_move_assignment,
-                    typename absl::allocator_traits<HasPropagateOnMove>::
-                        propagate_on_container_move_assignment>::value));
-  EXPECT_TRUE(
-      (std::is_same<std::false_type,
-                    typename absl::allocator_traits<
-                        A>::propagate_on_container_move_assignment>::value));
-
-  struct HasPropagateOnSwap {
-    using value_type = X;
-    struct propagate_on_container_swap {};
-  };
-
-  EXPECT_TRUE(
-      (std::is_same<HasPropagateOnSwap::propagate_on_container_swap,
-                    typename absl::allocator_traits<HasPropagateOnSwap>::
-                        propagate_on_container_swap>::value));
-  EXPECT_TRUE(
-      (std::is_same<std::false_type, typename absl::allocator_traits<A>::
-                                         propagate_on_container_swap>::value));
-
-  struct HasIsAlwaysEqual {
-    using value_type = X;
-    struct is_always_equal {};
-  };
-
-  EXPECT_TRUE((std::is_same<HasIsAlwaysEqual::is_always_equal,
-                            typename absl::allocator_traits<
-                                HasIsAlwaysEqual>::is_always_equal>::value));
-  EXPECT_TRUE((std::is_same<std::true_type, typename absl::allocator_traits<
-                                                A>::is_always_equal>::value));
-  struct NonEmpty {
-    using value_type = X;
-    int i;
-  };
-  EXPECT_TRUE(
-      (std::is_same<std::false_type,
-                    absl::allocator_traits<NonEmpty>::is_always_equal>::value));
-}
-
-template <typename T>
-struct AllocWithPrivateInheritance : private std::allocator<T> {
-  using value_type = T;
-};
-
-TEST(AllocatorTraits, RebindWithPrivateInheritance) {
-  // Regression test for some versions of gcc that do not like the sfinae we
-  // used in combination with private inheritance.
-  EXPECT_TRUE(
-      (std::is_same<AllocWithPrivateInheritance<int>,
-                    absl::allocator_traits<AllocWithPrivateInheritance<char>>::
-                        rebind_alloc<int>>::value));
-}
-
-template <typename T>
-struct Rebound {};
-
-struct AllocWithRebind {
-  using value_type = int;
-  template <typename T>
-  struct rebind {
-    using other = Rebound<T>;
-  };
-};
-
-template <typename T, typename U>
-struct AllocWithoutRebind {
-  using value_type = int;
-};
-
-TEST(AllocatorTraits, Rebind) {
-  EXPECT_TRUE(
-      (std::is_same<Rebound<int>,
-                    typename absl::allocator_traits<
-                        AllocWithRebind>::template rebind_alloc<int>>::value));
-  EXPECT_TRUE(
-      (std::is_same<absl::allocator_traits<Rebound<int>>,
-                    typename absl::allocator_traits<
-                        AllocWithRebind>::template rebind_traits<int>>::value));
-
-  EXPECT_TRUE(
-      (std::is_same<AllocWithoutRebind<double, char>,
-                    typename absl::allocator_traits<AllocWithoutRebind<
-                        int, char>>::template rebind_alloc<double>>::value));
-  EXPECT_TRUE(
-      (std::is_same<absl::allocator_traits<AllocWithoutRebind<double, char>>,
-                    typename absl::allocator_traits<AllocWithoutRebind<
-                        int, char>>::template rebind_traits<double>>::value));
-}
-
-struct TestValue {
-  TestValue() {}
-  explicit TestValue(int* trace) : trace(trace) { ++*trace; }
-  ~TestValue() {
-    if (trace) --*trace;
-  }
-  int* trace = nullptr;
-};
-
-struct MinimalMockAllocator {
-  MinimalMockAllocator() : value(0) {}
-  explicit MinimalMockAllocator(int value) : value(value) {}
-  MinimalMockAllocator(const MinimalMockAllocator& other)
-      : value(other.value) {}
-  using value_type = TestValue;
-  MOCK_METHOD(value_type*, allocate, (size_t));
-  MOCK_METHOD(void, deallocate, (value_type*, size_t));
-
-  int value;
-};
-
-TEST(AllocatorTraits, FunctionsMinimal) {
-  int trace = 0;
-  int hint;
-  alignas(TestValue) char buffer[sizeof(TestValue)];
-  auto* x = reinterpret_cast<TestValue*>(buffer);
-  MinimalMockAllocator mock;
-  using Traits = absl::allocator_traits<MinimalMockAllocator>;
-  EXPECT_CALL(mock, allocate(7)).WillRepeatedly(Return(x));
-  EXPECT_CALL(mock, deallocate(x, 7));
-
-  EXPECT_EQ(x, Traits::allocate(mock, 7));
-  static_cast<void>(Traits::allocate(mock, 7, static_cast<const void*>(&hint)));
-  EXPECT_EQ(x, Traits::allocate(mock, 7, static_cast<const void*>(&hint)));
-  Traits::deallocate(mock, x, 7);
-
-  EXPECT_EQ(0, trace);
-  Traits::construct(mock, x, &trace);
-  EXPECT_EQ(1, trace);
-  Traits::destroy(mock, x);
-  EXPECT_EQ(0, trace);
-
-  EXPECT_EQ(std::numeric_limits<size_t>::max() / sizeof(TestValue),
-            Traits::max_size(mock));
-
-  EXPECT_EQ(0, mock.value);
-  EXPECT_EQ(0, Traits::select_on_container_copy_construction(mock).value);
-}
-
-struct FullMockAllocator {
-  FullMockAllocator() : value(0) {}
-  explicit FullMockAllocator(int value) : value(value) {}
-  FullMockAllocator(const FullMockAllocator& other) : value(other.value) {}
-  using value_type = TestValue;
-  MOCK_METHOD(value_type*, allocate, (size_t));
-  MOCK_METHOD(value_type*, allocate, (size_t, const void*));
-  MOCK_METHOD(void, construct, (value_type*, int*));
-  MOCK_METHOD(void, destroy, (value_type*));
-  MOCK_METHOD(size_t, max_size, (),
-              (const));
-  MOCK_METHOD(FullMockAllocator, select_on_container_copy_construction, (),
-              (const));
-
-  int value;
-};
-
-TEST(AllocatorTraits, FunctionsFull) {
-  int trace = 0;
-  int hint;
-  TestValue x(&trace), y;
-  FullMockAllocator mock;
-  using Traits = absl::allocator_traits<FullMockAllocator>;
-  EXPECT_CALL(mock, allocate(7)).WillRepeatedly(Return(&x));
-  EXPECT_CALL(mock, allocate(13, &hint)).WillRepeatedly(Return(&y));
-  EXPECT_CALL(mock, construct(&x, &trace));
-  EXPECT_CALL(mock, destroy(&x));
-  EXPECT_CALL(mock, max_size()).WillRepeatedly(Return(17u));
-  EXPECT_CALL(mock, select_on_container_copy_construction())
-      .WillRepeatedly(Return(FullMockAllocator(23)));
-
-  EXPECT_EQ(&x, Traits::allocate(mock, 7));
-  EXPECT_EQ(&y, Traits::allocate(mock, 13, static_cast<const void*>(&hint)));
-
-  EXPECT_EQ(1, trace);
-  Traits::construct(mock, &x, &trace);
-  EXPECT_EQ(1, trace);
-  Traits::destroy(mock, &x);
-  EXPECT_EQ(1, trace);
-
-  EXPECT_EQ(17u, Traits::max_size(mock));
-
-  EXPECT_EQ(0, mock.value);
-  EXPECT_EQ(23, Traits::select_on_container_copy_construction(mock).value);
-}
-
 TEST(AllocatorNoThrowTest, DefaultAllocator) {
 #if defined(ABSL_ALLOCATOR_NOTHROW) && ABSL_ALLOCATOR_NOTHROW
   EXPECT_TRUE(absl::default_allocator_is_nothrow::value);